molar incisor hypomineralisation Flashcards
molar incisor hypomineralisation
systemic origin of 1-4 permanent molars, frequently associated with affected incisors
Only teeth MIH effects (first permanent molar and incisors)
Cheesy molars
- Yellow
- Obvious
Can be patches of yellow or white
molar appearance of molar incisor hypomineralisaton
Cheesy molars
- Yellow
- Obvious
Can be patches of yellow or white
incisor appearance of MIH
Well demarcated - blobs rather than diffuse
- Not symmetrical
Chalky white and yellow/brown parts
prevalence of MIH
10-20%
- increasing
hypomineralised
disturbance of enamel formation resulting in a reduced mineral content
later in amelogenesis
- secretory – jelly template
no issues, right shape - mineralisation – jelly to hard enamel
—-issue here – parts not as strong
cannot bond normally
- different structure to normal enamel, weaker areas
post-eruptive hypoplasia
hypomineralised FPMs erupt normal bit with soft enamel, parts fall out – then believe wrong morphology
- think hypoplastic but not truly
bonding issue in MIH
cannot bond normally
- different structure to normal enamel, weaker areas
what stage of amelogeneisis is affected in hypomineralisation
mineralisation (after secretory stage)
- enamel not as strong
hypoplastic
reduced bulk or thickness of enamel
- erupt amorphous (wrong shape - secretory phase wrong, but later mineralisation stage right)
May be:
- True - enamel never formed
- Aquired - post-eruptive loss of enamel bulk
\
bonding to hypoplastic enamel
Bond normally
normal enamel structure but not full coverage
what stage of amelogenesis is effected in hypoplastic enamel
wrong shape - secretory phase wrong, but later mineralisation stage right
why so difficult to determine aetiology of MIH
Unclear diagnostic criteria in classification
Most parents can’t remember details from 8-10 years before
- FPM begins forming before birth to age of 2 - Long time period ago
Variations in quality and completeness of case records
Study populations small
what is the critical period for formation of MIH
First year of life generally agreed (disturbance)
- Developmental (not hereditary, or genetic)
Enamel matrix of crown of FPM’s is complete by one year
3 clinical periods of enquiry for MIH
prenatal
natal (perinatal)
postnatal
questions to ask regarding prenatal period and MIH
Usually ask mothers about their general health in 3rd trimester of pregnancy
- Usually nothing really identified but possible causes can be e.g. Pre-eclampsia, gestational diabetes
no definitive causative factors identified
questions to ask regarding perinatal period and MIH
Birth trauma/anoxia
- particularly traumatic - emergency C section, suction cup, forceps, lack O2
Hypoclacemia
Preterm birth
- higher MIH rate than full term
questions to ask regarding postnatal period and MIH
Prolonged breast feeding (beyond 6 months)
- 50:50 inconclusive, don’t suggest don’t breast feed to avoid
Dioxins in breast milk
- 1 yes:2 no
Fever and medications (childhood infections: mumps, chicken pox etc)
- 100% yes
- antibiotics not cause enamel defect but reason on them does
Rural Vs Urban
- Yes
special care units, respiratory problems
measles Incubation period:
10-14 days
measles symptoms (6)
Fever Rash Koplik’s spots Conjunctivitis (eye – need sunglasses) Coryza (runny nose) Cough
measles Duration of illness
7-10 days
measles complications
Secondary infection, otitis media (middle ear infection)
bronchopneumonia
Corneal ulcers, stomatitis,
gastroenteritis, appendicitis
rubella symptoms (5)
mild fever
Maculopapular rash
Generalised lymphadenopathy (swollen gland) esp. suboccipital nodes
Malaise tired
URTI
rubella duration of illness
8-10 days
rubella complcations
rare
Encephalitis - brain swelling arthritis - join swelling
Purpura - severe rashes
what has been found to be a possible aetiological cause of MIH
Disturbances in nutrition during the first 6 months that may have an effect on MIH
Breastfeeding more > 6months
Late intro gruel > 6months
Late intro infant formula >6months
systemic disturbances in first 2 years of life has an impact
depth of effect if appearance is yellow/brown enamel
whole enamel layer MIH
- microabrasion
depth of effect if appearnace white/cream enamel
inner parts of enamel affected
- bleaching so less contrast with normal tissue
content of hypomineralised demarcated opacities
Higher carbon content, lower Ca, PO4
what is neural density like in MIH
Significant increases in neural density (nerve tissue) in the pulp horn and subodontoblastic region of MIH samples
More innervation
- more sensitive,
- harder to anaesthetise,
more neural densities
is there a difference in immune cell accumulation in MIH teeth
yes
Significant increases in immune cell accumulation in MIH samples, especially with post-eruptive enamel loss
is there a difference in vascularity in MIH teeth
yes
significant increase in vascularity in sensitive MIH teeth
- try and fix issue with more blood flow
3 potential pain mechanisms of MIH
dentine hypersensitivity
peripheral sensitisation
central sensitisation
DO NOT KNOW MIH PAIN MECHANISM EXACTLY
- know they are more sensitive
dentine hypersensitivity in MIH
porous enamel or exposed dentine facilitates fluid flow within dentine tubules to activate A-delta nerve fibres
- hydrodynamic theory
peripheral sensitisation in MIH
underlying pulpal inflammation leads to sensitisation of C-fibres
- more neural C fibres there in first place
central sensitisation in MIH
from continued nociceptive input
- come from brain, due to continue assault on teeth
3 clinical problems due to MIH
Loss of tooth substance - Breakdown of enamel - Tooth wear - Secondary caries (Perfectly good primary dentition, FPM 6 months has caries – poor caries resistance)
Sensitivity
- Can be exquisitely sensitive
- —-More caries as hurt to brush
Appearance (esp anterior, psychological issues)
MIH treatment options (4)
Composite/GIC restorations
- Make them tougher and more wear resistant
Stainless steel crowns
Adhesively retained copings
- Au, glass, composite
Extraction (8.5 - 9.5 yrs)
- majority of moderate to severe – use their dental age
what do you need to see radiographically to extract FPMs
Want to see calcification of bifurcation of lower 7 than can extract lower 6s
- Before 7 erupts will drift forwards
Take out upper 6s at same time - Need to so don’t over erupt
- Potentially crowded – loss of space due to primary molars extraction, keep upper 6s till 7s come through as risk of losing good premolars for space
- Longer ortho treatment but more natural teeth
4 considerations for extractions of HFPMs
age (dental age)
skeletal pattern (prevent future ortho problems)
future othrodontic needs
quality of teeth e.g. caries
5 treatments of affected hypo-mineralised incisors
Acid pumice microabrasion
- Yellow or brown marks removed
External bleaching
- Cant get white chalkiness to go away, but can reduce contrast with rest of tooth
Localised composite placement
- Less likely to eradicate but make less difference between
Full composite veneers
Full porcelain veneers
- Gum level changes between 16 and 20 – so avoid as expose margins and wear tooth down
what is required for microabrasion and external bleaching
full permanent dentition
- 11-13 yrs
